Near UV excited SrAl2O4:Dy3+ phosphors for white LED applications

Strontium aluminate phosphors containing different concentrations of Dy3+ ions (SrAl2O4:Dy3+) were prepared by solid state reaction method by sintering at 1100 degrees C for 3 h. These phosphors were crystallized into monoclinic structure and well consistent with the JCPDS No. 34-0379. All these phos- phors exhibit the characteristic emission transitions such as F-4(9/2) -> H-6(15/2), F-4(9/2) -> H-6(13/2) and F-4(9/2) -> H-6(11/2) corresponding to blue (similar to 480 nm), yellow (similar to 572 nm) and red (similar to 663 nm) regions when excited at 350 nm near UV wavelength. Beyond 1.0 mol% concentration of Dy3+ ions, a luminescence quenching was noticed and it has been assigned to the energy transfer through dipole-dipole interactions at higher concentrations. Due to crystallization into nanophase, the SrAl2O4:Dy3+ phosphors exhibit novel and excellent luminescence properties at 350 nm excitation. The 1.0 mol% of Dy3+-doped SrAl2O4 phosphor show a quantum yield of similar to 9.52%. The experimental results suggest that the SrAl2O4:1.0 mol% Dy3+ phosphor could be the best choice to design white LEDs with bright and intense luminescence. (C) 2018 Elsevier B.V. All rights reserved.